1. Field of the Invention
The present invention relates to an air intake noise reduction apparatus for an automotive vehicle for reducing air intake noise using an air intake noise reduction duct for inducting air into an engine.
2. Description of Related Art
A single-stage interference-type air intake noise reduction apparatus and a multi-stage resonance-type air intake noise reduction apparatus are known as an air intake noise reduction apparatus for reducing air intake noise originating from an internal combustion engine of an automotive vehicle. As shown in FIG. 10A, the single-stage interference-type air intake noise reduction apparatus is constructed so as to exhibit an air intake noise reduction effect through interference between pulsating air in an air intake passage 01 and pulsating air in a by-pass passage 02 formed as part of the air intake passage 01 whose phases are shifted due to the difference in length L1, L2 of the air intake passage 01 and the by-pass passage 02. In addition, as shown in FIG. 10B, the multi-stage resonance-type air intake noise reduction apparatus is constructed so as to exhibit an air intake noise reduction effect through resonance of air in a plurality of integrally formed resonance chambers 03, 04 which are made to communicate with an air intake passage 05.
Moreover, Japanese Patent Unexamined Publication (Kokai) No. Hei.8-158965 describes an air intake noise reduction apparatus in which an expansion-type air intake noise reduction apparatus and a resonance-type air intake noise reduction apparatus are integrally provided in a common air intake noise reduction case.
With the single-stage interference-type air intake noise reduction apparatus shown in FIG. 10A, since it is single-staged, not only does the frequency range become narrow where the air intake noise reduction effect is exhibited, but also there needs to form the by-pass passage separately from the air intake passage, these resulting in disadvantages in cost and space. If this single-stage construction is transformed into a multi-stage construction, the air intake noise reduction effect can be exhibited within a wider frequency range, but it gets more disadvantageous in terms of cost and space.
With the multi-stage resonance-type air intake noise apparatus shown in FIG. 10B, since it needs wider space, not only does the size of the apparatus have to get larger, but also the construction of the apparatus gets complicated, which makes it difficult to mold components required for such a complicated construction, thus leading to a problem of increase in cost.
Furthermore, Japanese Patent Unexamined Publication No. HEI 8-158965 also describes an air intake noise reduction apparatus which is so complicated in construction that molding of components required for such a complicated construction becomes difficult, thus posing a problem of increase in cost, as well as a problem of increase in man-hour for assembly of a large number of components attributed to the complicated construction.
The present invention was made in view of the aforesaid circumstances, and it is an object of the present invention to provide an air intake noise reduction apparatus for effectively reducing air intake noise, although it is simple in construction and therefore requires a small number of components.
With a view to attaining the aforesaid object, according to a first aspect of the present invention, there is provided an air intake noise reduction duct for an automotive vehicle for reducing air intake noise with an air intake noise reduction duct for inducting air into an engine of the automotive vehicle, wherein a plurality of air intake passages which each have different passage lengths are formed by partitioning the air intake noise reduction duct with partition walls.
In the present invention, the object can be achieved by an air intake noise reduction apparatus for an automotive vehicle for reducing air intake noise with an air intake noise reduction duct for inducting air into an engine of the automotive vehicle, wherein a plurality of air intake passages which each have different passage lengths are formed by partitioning the air intake noise reduction duct with partition walls.
According to the above construction, although the apparatus is constructed as a compact and low-cost construction comprising only the partition walls provided in the air intake noise reduction duct, air intake noise can effectively be reduced by forming the plurality of air intake passages which each have different passage lengths, and in addition, the rigidity of the air intake noise reduction duct can be increased with the partition walls functioning as a reinforcement rib.
In the above-mentioned construction, it is advantageous that the partition walls extend along an intake air flow direction.
Since the partition walls are formed in such a manner as to extend along the air intake direction, the increase in intake air resistance can be suppressed to a minimum level.
In addition, according to a second aspect of the invention, there is provided an air intake noise reduction apparatus for an automotive vehicle for reducing air intake noise with an air intake noise reduction duct for inducting air into an engine of the automotive vehicle, wherein a plurality of air intake passages which each have different passage lengths are formed by connecting together opposed walls which each have the largest surface area of a flat portion provided as part of the air intake noise reduction duct with partition walls extending along an air intake direction.
According to the above construction, although the apparatus is constructed with a compact and low-cost construction comprising only the partition walls provided in the air intake noise reduction duct, air intake noise can effectively be reduced by forming the plurality of air intake passages which each have different passage lengths, and in addition, since the partition walls connecting together the opposed walls each having the largest surface area of the flat portion function as a reinforcement rib, the rigidity of the air intake noise reduction duct can be increased to thereby effectively prevent membrane surface vibrations. Moreover, since the air intake noise reduction duct has the flat portion, the apparatus can be disposed even in a narrow space in an engine compartment.
Furthermore, according to a third aspect of the invention, there is provided an air intake noise reduction apparatus for an automotive vehicle for reducing air intake noise with an air intake noise reduction duct for inducting air into an engine of the automotive vehicle, wherein a plurality of air intake passages which each have different passage lengths are formed by partitioning a curved portion provided in the air intake noise reduction duct with partition walls extending in such a manner as to conform to a curved configuration of the curved portion.
According to the above construction, although the apparatus is constructed as a compact and low-cost construction comprising only the partition walls provided in the air intake noise reduction duct, air intake noise can effectively be reduced by forming the plurality of air intake passages which each have different passage lengths, and in addition, the rigidity of the air intake noise reduction duct can be increased with the partition walls functioning as a reinforcement rib. Moreover, since the curved portion of the air intake noise reduction duct is partitioned with the partition walls extending in such a manner as to conform to the curved configuration of the curved portion, not only can the air intake noise reduction duct be made compact further in size, but also the increase in intake air resistance can be suppressed by straightening the flow of air at the curved portion.
In addition, according to a fourth aspect of the invention, there is provided an air intake noise reduction apparatus for an automotive vehicle as set forth in the third aspect of the present invention, wherein the length of the partition walls is made shorter as the partition walls are situated more radially inwardly of the curved portion.
According to the above construction, since at least three air intake passages are formed with at least two partition walls, the air intake noise reduction effect can be enhanced. In addition thereto, since the length of the partition wall situated more radially inwardly in the curved portion becomes shorter, the air intake noise reduction duct can further be made compact in size.
Moreover, according to a fifth aspect of the invention, there is provided an air intake noise reduction apparatus for an automotive vehicle for reducing air intake noise with an air intake noise reduction duct for inducting air into an engine of the automotive vehicle, wherein a plurality of air intake passages which each have different passage lengths are formed by partitioning an air intake noise reduction duct with partitioning walls, and wherein the direction of intake air flow and the direction of the partition walls are made to intersect each other at an entry portion of the air intake noise reduction duct.
According to the above construction, although the apparatus is constructed as a compact and low-cost construction comprising only the partition walls provided in the air intake noise reduction duct, air intake noise can effectively be reduced by forming the plurality of air intake passages which each have different passage lengths, and in addition, the rigidity of the air intake noise reduction duct can be increased with the partition walls functioning as a reinforcement rib. Moreover, since the direction of intake air flow and the direction of the partition walls are made to intersect each other at an entry portion of the air intake noise reduction duct, penetration of water or the like into the interior of the air intake noise reduction duct can be checked.
The present disclosure relates to subject matter contained in Japanese Patent Application No. Hei. 10-297113, filed on Oct. 19, 1998, and which is expressly incorporated herein by reference in its entirety.